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Calculator

Battery Sizing Calculator

Calculate the battery bank size you need based on daily energy consumption, backup duration, and depth of discharge requirements.

Continuously maintained3 min read Focus Solar Editorial Team Reviewed for technical accuracy through the Focus Solar editorial process

Enter your daily load, desired backup hours, and battery chemistry to get a recommended battery bank capacity in kWh. The calculator accounts for depth of discharge limits and system voltage to help you specify the correct number of battery units.

YOUR INPUTS

Estimate battery capacity

Adjust the assumptions. Results update immediately.
kWh/day
Range 1–300
hours
Range 1–72
%
Range 40–100
%
Range 60–100
Planning estimate only

How to use this estimate

This result is an early decision aid, not an approved electrical or structural design. Weather, shading, orientation, equipment efficiency, local rules, and actual product specifications can change the outcome.

Regional differences: Costs, taxes, incentives, tariffs, and grid rules vary by location and over time.

Read the calculation methodology →